Temperature modulated draft system for incinerator

ABSTRACT

A conical-shaped, industrial type, waste incinerator having a temperature modulated forced draft system including a blower and an air inlet conduit for discharging forced air into the combustion chamber. The incinerator is also provided with concentric double walls about the combustion chamber to provide insulation and also to provide means for cooling the outer skin. The air inlet conduit is provided with a cooling branch conduit connected to the space between the double walls. The diverter valve means is located in the air inlet conduit for selectively, and alternately, opening and closing the respective air inlet conduit and cooling branch conduit. The valve selection means is controlled and modulated by an electrical apparatus responsive to the temperature within the combustion chamber. The incinerator may also be provided with an exit gas temperature sensor for shutting down the blower when the temperature in the exhaust opening of the incinerator is excessive. The incinerator also preferably includes a variable emission gate means mounted in the exhaust opening having variable radial vanes which are adapted to be moved between open and closed positions by an electrical control responsive to the exit gas temperature sensor.

United States Patent 1 Franklin 11] 3,710,738 Jan. 16, 1973 [22] Filed:

[54] TEMPERATURE MODULATED DRAFT SYSTEM FOR INCINERATOR [75] Inventor:

Tex.

[73] Assignee: Steelcraft Corporation, Memphis,

Tenn.

Aug. 12, 1971 [21] Appl. No.: 171,162

[56] References Cited UNITED STATES PATENTS 1,339,729 5/1920 Walsh ..ll0/18 3,524,418 8/1970 Cowan .....1l0/l8 3,638,591 2/1972 Lausmann ..110/18 Primary ExaminerKenneth W. Sprague Attorney-Harrington A. Lackey David M. Franklin, Jacksonville,

[57] ABSTRACT A conical-shaped, industrial type, waste incinerator having a temperature modulated forced draft system including a blower and an air inlet conduit for discharging forced air into the combustion chamber. The incinerator is also provided with concentric double walls about the combustion chamber to provide insulation and also to provide means for cooling the outer skin. The air inlet conduit is provided with a cooling branch conduit connected to the space between the double walls. The diverter valve means is located in the air inlet conduit for selectively, and alternately, opening and closing the respective air inlet conduit and cooling branch conduit. The valve selection means is controlled and modulated by an electrical apparatus responsive to the temperature within the combustion chamber.

The incinerator may also be provided with an exit gas temperature sensor for shutting down the blower when the temperature in the exhaust opening of the incinerator is excessive.

The incinerator also preferably includes a variable emission gate means mounted in the exhaust opening having variable radial vanes which are adapted to be moved between open and closed positions by an electrical control responsive to the exit gas temperature sensor.

10 Claims, 8 Drawing Figures PATENTEDJAN 16 I973 SHEET 1 BF 2 INVENTOR 1 wDMfkmv/a/N AT RNEY f g mu TEMPERATURE MODULATED DRAFT SYSTEM FOR INCINERATOR BACKGROUND OF THE INVENTION This invention relates to an industrial type incinerator, and more particularly to a temperature modulated draft system for the incinerator.

Conical or tepee-type incinerators are welLknown in the art. Furthermore, forced draft systems for such in- SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a temperature modulated forced draft system for a tepeetype incinerator in which air is selectively forced into the combustion chamber and circulated to cool the incinerator wall, in varying amounts corresponding to the temperature within the combustion chamber.

A Y-type air inlet conduit, including a combustion outlet branch conduit and a cooling outlet branch conduit, are connected to the outlet end of the blower. The combustion branch is connected to the under-fire and/or over-fire outlets within the bottom or floor of the incinerator. In the preferred form of the invention, the cooling branch is connected to the space between the walls of a double walled incinerator. A diverter valve means or mechanism is provided in the air conduit between the outlet of the blower and the two branch conduits in such a manner that each branch conduit may be selectively and alternately opened and closed. That is, when the combustion branch conduit is diverter valve mechanism may occupy any position between open and closed.

The selection of the position of the diverter valve mechanism is determined by an electrical motor connected to an electrical control device, which in turn is responsive to thermocouples or thermoelectric sensors within the combustion chamber. As burning commences within the combustion chamber, the combustion branch conduit is wide open, while the cooling branch is closed. As the temperature increases within the combustion chamber, the diverter valve mechanism gradually closes the combustion conduit while gradually opening the cooling conduit as the demand for combustion air gradually decreases and the requirement for cooling the walls of the incinerator increases. When the temperature within the combustion chamber has attained the desired operating range, then the position of the diverter valve mechanism will be substantially balanced to maintain the desired openings within each of the branch conduits for a set operating temperature.

Since the diverter valve mechanism merely diverts air from one branch conduit to another, there is no barrier to the flow of air from the blower, and consequently the load on the blower remains substantially constant.

This invention also contemplates exit gas thermoelectric sensor or thermocouple in the stack or exhaust opening of the incinerator so that, when an excessive exit gas temperature is sensed, the blower may be shut off and an alarm may be sounded in order to apprise the operator of the dangerous heating conditions within the incinerator.

The invention also contemplates an emission gate 7 means or mechanism within the exhaust opening pro- 0 vided with circumferential vanes, rotatable about radial axes, for varying the passage of products of combustion through the exhaust opening. These vanes may be gradually opened and closed manually, or they may be controlled by an electrical motor winch means, which in turn is modulated by the exit gas sensor.

By employing the modulated diverter valve means as well as the separately modulated emission gate means, a very high degree of control may be obtained over the combustion of the waste material as well as the discharge of the emission products.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional elevation of a tepee incinerator and a temperature modulated forced draft system made in accordance with this invention;

FIG. 2 is a fragmentary section taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged, fragmentary, side elevation, with parts broken away, of the diverter valve mechanism;

FIG. 4 is a fragmentary top plan view of the exhaust opening, with parts broken away, to disclose the emission gate mechanism in closed position;

FIG. 5 is a fragmentary section taken along the line 5-5 of FIG. 4;

FIG. 6 is a view similar to FIG. 5, with the emission gate mechanism in open position;

FIG. 7 is an enlarged fragmentary section taken along the line 7-7 of FIG. 4; and

FIG. 8 is an enlarged fragmentary section taken along the line 8-8 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to FIG. 1 the tepeetype incinerator 10 made in accordance with this invention includes a conical-shaped outer wall 11 supported in an upright position-upon any type of base or floor 12.

Mounted in the floor 12 of the incinerator 10 are a plurality of under-fire discharge outlets or grates 14, of a well-known type, to discharge air up through the bottom of the waste material to be burned. The under-fire air discharged into the waste material produces turbulence, which breaks up and exposes unburned material to the flames.

Mounted-circumferentially around the under-fire discharge outlets 14 are a plurality of over-fire discharge elbows or outlets 15, also of a well-known type, to discharge forced air around and over the waste material in a spiral circulation to increase the combustion of the waste products in the pile 16. All of the under-fire outlets l4 and over-fire outlets 15 may be fed through respective conduits from a manifold 17 connected to the combustion branch conduit 18 of the air inlet conduit 19. Air is forced through the air conduit 19 from the atmosphere by blower 20 driven by electric motor 21.

Mounted concentrically within the outer incinerator wall 11 is a conical inner wall 23 creating an intermediate cooling space 24 between the inner wall 23 and the outer wall 1 l.

The air inlet conduit 19 is preferably Y-shaped, its inlet end being connected to the blower 20, one outlet end being connected to the combustion branch conduit 18, and its other outlet end being connected to the cooling branch conduit 25. The opposite end of the cooling conduit 25 extends through the outer wall 11 to communicate with the cooling space 24 through its outlet end 26.

As best disclosed in FIG. 3, a diverter valve mechanism 27 is mounted in the air conduit 19. The diverter valve mechanism 27 includes an upper or cooling valve 28 fixed on pivot shaft 29 journaled in the entrance to the cooling conduit 25. The diverter valve mechanism 27 also includes a lower or combustion valve 30 fixed upon pivot shaft 31 journaled within the entrance to the combustion conduit 18. To each pivot shaft 29 and 31 is fixed a crank arm 32 and 33, respectively, both of which are pivotally connected by the adjustable connecting rod 23. Link rod 35 is pivotally connected to the upper crank arm 32 and to the motor crank arm 36 of a reversible, electric operator motor 37. Thus, as the motor 37 is driven in one direction or the other,'the cooling and combustion valves 28 and 30 are moved simultaneously in the same rotary direction.

As disclosed in FIG. 3, the upper or cooling valve 28 is closed in solid-line position and open in phantom, while the lower or combustion valve 30 is open in solidline position and closed in phantom, just reverse from the cooling valve 28. Although the solid-line and phantom valve positions are the extreme open and closed positions of these valves, the operator motor 37 is adapted to move the valves 28 and 30 to any intermediate position to partially open both branch conduits 25 and 18.

An electrical control panel 40 is mounted adjacent the incinerator 10 and is connected to the blower motor 21 through electrical lead 41 and to the operator motor 37 through electrical lead 42.

Mounted within the combustion chamber 44, above the pile of waste material 16 is a plurality of thermoelectric sensors or thermocouples 45 spaced transversely of the walls 11 and 23. The thermal sensors 45 are connected through lead 46 to the electrical control panel 40. The thermocouples 45 are connected in an integrated circuit within the control panel 40 in order to produce an electrical signal which corresponds to the average temperature across the combustion chamber 44. The signal is proportional to, or corresponds to, the temperature within the combustion chamber 44 and controls electronic circuitry within the control panel 40 for driving the operator motor 37. As the temperature increases in the combustion chamber 44, the combustion valve 30 and the cooling valve 28 rotate in the clockwise direction of the arrows from their solid-line to their phantom positions. Accordingly, the combustion valve 30 moves from an open position toward a closed position, while the cooldecreasing within the combustion chamber 44, the valves 30 and 28 rotate counterclockwise from their phantom to their solid line positions, as disclosed in 1 FIG. 3.

In this manner, as combustion develops within the combustion chamber 44 and the temperature rises, less air is needed. Accordingly, less air is fed through the combustion branch conduit 18, both to the under-fire and to the over-fire outlets l4 and-l5. Simultaneously, more air is bypassed through the cooling branch conduit 25 to increase the cooling effect within the space 24 between the outer wall 11 and the inner wall 23. Accordingly, the outer wall 11 is maintained cool relative to the inner wall 23, not only because of the insulation effect of the air between the walls, but also because of the cooling effect of the rapidly moving cool air introduced from the atmosphere. As the air within the space 24 becomes heated, it rises and passes out through the exhaust opening defined by the dome 51.

Waste material, such as that represented in the pile 16 is fed into the incinerator 10 by any convenient means, such as a belt conveyor 48 extending through a loading opening 49 through the walls 11 and 23.

In a preferred form of the modulating system, an exit gas thermoelectric sensor or thermocouple 50 is mounted within the exhaust opening or stack 51 of the incinerator 10. The upper temperature sensor 50 is connected through lead 52 to the control panel 40, and is adapted, when sensing a predetermined excessive temperature within the exhaust opening 51, to open the circuit 41 to the blower motor 21. The control panel 40 may also be provided with an alarm signal, either audible or visual, to indicate the sensed excessive temperature within the exhaust opening 51 to apprise the operator of the dangerous heating condition within the incinerator l0.

Mounted within the stack 51 is an emission gate means or mechanism 55. The emission gate means 55 includes a circular platform 56 supported by a tubular standard 57 from a framework 58 fixed in the cylindrical stack 51. The circular platform 56 is of a smaller diameter than, and concentric with, the stack5l. Supported within the annular opening around the platform 56 are a plurality of wedge-shaped vanes 60. The vanes 60 are spaced in overlapping relationship circumferentially around the platform 56 to close the annular space between the platform 56 and the stack 51. Each vane 60 is provided with an elongated lateral lip 61 adapted to overlie and engage the adjacent edge of the next vane 60. Extending longitudinally of each vane and radially of the dome is a pivot rod 62fixed at its opposite ends between the circular platform 56 and the circular stack 51. Each pivot rod 62 is journaled in bearings 63 fixed along the middle of each vane 60 for rotary movement about a radial a'xis.

In order to open or close the'vanes 60 simultaneously, a sleeve 65 is slidably mounted upon the standard 57, and supports through turnbuckles 66 a carrier ring 67. Depending at spaced circumferential intervals from the carrier ring 67 are a plurality of link or actuator rods 68, the lower ends of which are pivotally connected by connectors 69 fixed to the top of each vane 60 and spaced circumferentially from each corresponding pivot rod 62. A hanger rod 70 is fixed transversely of the sleeve 65 and extends through opposed vertical slots in the hollow tubular standard 57 for limited vertical movement defined by the extremities of the slot 71. Attached to the hanger rod 70 is a flexible linear member, such as cable 72, extending up through the hollow standard 57 and over guide sheaves 73 and 74 down through the guide sleeves 75 and 76. The lower end of the cable 72 is fixed to a winch 77 driven by a reversible electric motor 78. The electric motor 78 is connected through lead 79 to the control panel 40, where it is connected through appropriate circuitry, not shown, and lead 52 to the exit gas temperature sensor 50. Accordingly, the vanes 60 may be moved to any position between the closed positions disclosed in FIG. 5 and the open positions disclosed in FIG. 6, depending upon the temperature sensed by the thermocouple 50. If the thermocouple 50 senses a comparatively cool exit gas temperature within the exhaust opening or stack 51, then the winch motor 78 is driven to move the vanes 60 toward a closed position in order to hold the products of combustion within the incinerator 10.

It has been found through experiment, that many solid products of combustion, such as flyash, may be further consumed by combustion, merely by hot gases at high temperatures, without a flame.

When the thermocouple 50 senses high temperatures in the exit gases, then the winch motor 78 is driven in the opposite direction to open the vanes 60 to a degree determined by the value of the temperature of the exit gases. Accordingly, the very hot combustion gases are removed from the interior of the incinerator to prevent excessive heating.

It is therefore evident from the modulated draft system in the form of either the diverter valve mechanism 27 or the emission gate mechanism 55, and their respective temperature sensors 45 and 50, that the causes of pollution from the combustion of waste products are attacked in their inception, by providing more efficient combustion, as well as by retaining products of incomplete combustion within the zones of high temperature for conversion to smaller particles or into hot gases.

Thestack 51 is also covered with a screen 80 to mechanically prevent'discharge of solid particles of emission of excessive sizes to the atmosphere.

What is claimed is: I

l. A draft system for an incinerator having a body enclosing a combustion chamber and an exhaust opening in the top of said body communicating with said combustion chamber, comprising:

a. an inlet air conduit having an inlet end and a discharge end communicating with said combustion chamber,

a branch outlet communicating with said air conduit between said inlet end and said discharge end, diverter valve means, means mounting said diverter valve means in said air conduit to move between a first position opening the passage of air between said inlet end and said dischargeend and closingthe passage of air through said branch outlet, and a second position opening the passage of air between said inlet end and said branch outlet and-closing the passage of air through said discharge end, means for selectively moving said diverter valve means to any position between said first and second positions to vary the ratio of air passing through said discharge end and said branch outlet from said inlet end, and i f. means for drawing air through said air conduit from said inlet end.

2. The invention according to claim 1 further comprising electrical motor means operatively connected to said valve means, thermo-electric sensors in said combustionchamber, and an electrical control device connected to said sensors and said motor, whereby increasing temperatures sensed by said sensors cause said valve means to move toward said second position, and decreasing temperatures sensed by said sensors cause said valve means to move toward said first position.

3. The invention according to claim 1 in which said body comprises a pair of spaced walls surrounding said combustion chamber, and said branch outlet comprises a branch conduit connecting said inlet air conduit to the space between said walls whereby air passing through said branch conduit from said inlet air conduit will flow between the walls of said body.

4. The invention according to claim 3 further comprising a plurality of thermo-electric sensors in said combustion chamber and spaced across the path of the combustion products, an electrical control device corinected to said sensors so hat said sensors produce an average temperature signal, and an electrical motor operatively connected to said valve means and controlled by said control device for varying the position of said valve means corresponding to the change in temperature sensed by said sensors.

5. The invention according to claim 3 in which said diverter valve means comprises a combustion valve mounted in said air conduit between said branch conduit and said discharge end and a cooling valve mounted in said branch conduit, link means connecting said combustion and cooling valves for simultaneous movement, said means for selectively moving said diverter valve means comprising an electrical motor operatively connected to said link means, and temperature control means responsive to the temperature in said combustion chamber for driving said electrical motor means;

6. The invention according to claim 3 further comprising emission gate means mounted in said exhaust opening, first electrical control means for varying the position of said gate means in order to vary the degree of passage of products of emission through said exhaust opening, an exit gas thermo-electric sensor in said exhaust opening, second electrical control means coupling said exit bas sensor to said first control means for varying the positions of said emission gate means corresponding to the change in exit gas temperatures.

7. A draft system for an incinerator having a body enclosing a combustion chamber and an exhaust opening in the top of said body communicating with said combustion chamber, comprising:

a. an inlet air conduit communicating with said combustion chamber,

b. means for forcing air through said conduit into said combustion chamber,

c. an emission gate frame mounted in said exhaust opening,

d. a plurality of vanes within said exhaust opening,

e. means mounting each vane on said gate frame for rotary movement about a radial axis between a closed position in which all said vanes are disposed in substantially the same plane, and an open position permitting emission products to pass between said vanes and through said exhaust opening, and

f. actuator means for opening and closing said vanes simultaneously.

8. The invention according to claim 7 in which said actuator means comprises a standard projecting up from said emission gate frame, a carrier member vertically movable upon said standard, link means connecting each vane to said carrier member, and means for raising and lowering said carrier member to close and open said vanes.

9. The invention according to claim 8 in which said means for raising and lowering said carrier member comprises reversible electrical motor means, an exit gas thermo-electric sensor mounted in said exhaust opening, an electrical control device connected to said exit gas sensor and said electrical motor means, whereby said motor means is energized to move said vanes to a closed position when said temperature sensed by said sensor is decreasing and to move said vanes to an open position when the temperature sensed by said sensors is increasing. I v

10. The invention according to claim 8 in which said carrier member comprises a sleeve slidably movable upon said standard, a ring member supported by said sleeve concentrically of said standard, said link means comprising a link arm connecting each vane to said ring member. 

1. A draft system for an incinerator having a body enclosing a combustion chamber and an exhaust opening in the top of said body communicating with said combustion chamber, comprising: a. an inlet air conduit having an inlet end and a discharge end communicating with said combustion chamber, b. a branch outlet communicating with said air conduit between said inlet end and said discharge end, c. diverter valve means, d. means mounting said diverter valve means in said air conduit to move between a first position opening the passage of air between said inlet end and said discharge end and closing the passage of air through said branch outlet, and a second position opening the passage of air between said inlet end and said branch outlet and closing the passage of air through said discharge end, e. means for selectively moving said diverter valve means to any position between said first and second positions to vary the ratio of air passing through said discharge end and said branch outlet from said inlet end, and f. means for drawing air through said air conduit from said inlet end.
 2. The invention according to claim 1 further comprising electrical motor means operatively connected to said valve means, thermo-electric sensors in said combustion chamber, and an electrical control device connected to said sensors and said motor, whereby increasing temperatures sensed by said sensors cause said valve means to move toward said second position, and decreasing temperatures sensed by said sensors cause said valve means to move toward said first position.
 3. The invention according to claim 1 in which said body comprises a pair of spaced walls surrounding said combustion chamber, and said branch outlet comprises a branch conduit connecting said inlet air conduit to the space between said walls whereby air passing through said branch conduit from said inlet air conduit will flow between the walls of said body.
 4. The invention according to claim 3 further comprising a plurality of thermo-electric sensors in said combustion chamber and spaced across the path of the combustion products, an electrical control device connected to said sensors so hat said sensors produce an average temperature signal, and an electrical motor operatively connected to said valve means and controlled by said control device for varying the position of said valve means corresponding to the change in temperature sensed by said sensors.
 5. The invention according to claim 3 in which said diverter valve means comprises a combustion valve mounted in said air conduit between said branch conduit and said discharge end and a cooling valve mounted in said branch conduit, link means connecting said combustion and cooling valves for simultaneous movement, said means for selectively moving said diverter valve means comprising an electrical motor operatively connected to said link means, and temperature control means responsive to the temperature in said combustion chamber for driving said electrical motor means.
 6. The invention according to claim 3 further comprising emission gate means mounted in said exhaust opening, first electrical control means for varying the Position of said gate means in order to vary the degree of passage of products of emission through said exhaust opening, an exit gas thermo-electric sensor in said exhaust opening, second electrical control means coupling said exit bas sensor to said first control means for varying the positions of said emission gate means corresponding to the change in exit gas temperatures.
 7. A draft system for an incinerator having a body enclosing a combustion chamber and an exhaust opening in the top of said body communicating with said combustion chamber, comprising: a. an inlet air conduit communicating with said combustion chamber, b. means for forcing air through said conduit into said combustion chamber, c. an emission gate frame mounted in said exhaust opening, d. a plurality of vanes within said exhaust opening, e. means mounting each vane on said gate frame for rotary movement about a radial axis between a closed position in which all said vanes are disposed in substantially the same plane, and an open position permitting emission products to pass between said vanes and through said exhaust opening, and f. actuator means for opening and closing said vanes simultaneously.
 8. The invention according to claim 7 in which said actuator means comprises a standard projecting up from said emission gate frame, a carrier member vertically movable upon said standard, link means connecting each vane to said carrier member, and means for raising and lowering said carrier member to close and open said vanes.
 9. The invention according to claim 8 in which said means for raising and lowering said carrier member comprises reversible electrical motor means, an exit gas thermo-electric sensor mounted in said exhaust opening, an electrical control device connected to said exit gas sensor and said electrical motor means, whereby said motor means is energized to move said vanes to a closed position when said temperature sensed by said sensor is decreasing and to move said vanes to an open position when the temperature sensed by said sensors is increasing.
 10. The invention according to claim 8 in which said carrier member comprises a sleeve slidably movable upon said standard, a ring member supported by said sleeve concentrically of said standard, said link means comprising a link arm connecting each vane to said ring member. 